Wet and dry pressing are widely practiced forming processes for compaction and shaping of fine powder using rigid dies or flexible molds (see, for example, J. S. Reed, “Principles of Ceramic Processing, 2nd edition, John Wiley & Sons, New York, 1988, incorporated by reference). These process have been used in the preparation of a wide variety of products including medicinal pellets, household pellet products such as bleach pellets for the swimming pool, magnetic and dielectric ceramics, various fine-grained technical alumina including chip carriers and spark plugs, engineering ceramics such as cutting tools and refractory sensors, ceramic titles and porcelain products, and coarse-grained refractories, grinding wheels, structural clay products, and nuclear fuel rods.
Objects pressed from powder are known in the art as green bodies. Green bodies are not very dense, but can be converted to hard dense compacts by sintering, which involves heating to temperatures that promote fusion of particles making up the green body.
Fine powder does not flow easily into a die because of high surface friction among the individual powder particles. The industrial practice is to convert fine powder into uniformly coarse powder by a process called granulation (see for example, J. R. Wood, “Tablet Manufacture, Its History, Pharmacy and Practice, J. B. Lippincott Company, Philadelphia & London, 1906, incorporated by reference). Granulated powder flows more easily into dies. Granulated powder is composed of deformable granules that are stable under ambient conditions.
Organic binders and plasticizers are sometimes added to granulated powder. These organic additives serve as a deformable medium and are believed to play a role in retaining the shape and structure of the granule. However, these organic additives can degrade in a radioactive environment. If the granulated powder itself were composed of radioactive materials, the emitted radioactivity would degrade the organic additives. Granulated radioactive powder may be needed for applications such as for nuclear fuel applications. Thus, there is a need for granulated powder of radioactive materials that is deformable and is also free from organic additives such as binders and plasticizers.